LaTeX Class and Package

In general, the $\(\LaTeX\)$ typesetting setting are set up by specifying the class and package of the $\(\LaTeX\)$ typesetting document.

Classes and Packages

Class command, \documentclass and package command, \usepackage are used to specify the general properties of the LaTeX typeset document to be constructed. Only one document class can be specified and more than one package can be specified.

Commands

Commands

\documentclass[⟨options⟩]{⟨class⟩}
\usepackage[⟨options⟩]{⟨packages⟩}

Extensions

Document classes end with ".cls" and packages end with ".sty".

Example

Example 1

\documentclass[twoside]{article}
\usepackage{dvips]{graphics}
\usepackage{dvips]{color}

Example 2

\documentclass[twoside]{article}
\usepackage{dvips]{graphics, color}

Standard Classes

The standard classes distributed with LaTeX:

Standard Packages

The standard packages distributed with LaTeX:

Related Software

The following software should be available from the same distributor as your copy of LateX2e. You should obtain at least the graphics and tools collections in order to have all the files described in LaTeX: A Document Preparation System. The amsmath package (part of amslatex and formerly known as amstex) and babel are also mentioned in the list of ‘standard packages’ in section C.5.2 of that book. These packages come with documentation and each of them is also described in at least one of the books The LaTeX Companion and LaTeX: A Document Preparation System.

Tools

This collection of packages includes, at least, the following (some files may have slightly different names on certain systems):

Commands

Preamble Command

Preamble commands should be used only before \begin{document}

\documentclass

\documentclass [⟨option-list⟩] {⟨class-name⟩} [⟨release-date⟩]

This command replaces the LaTeX 2.09 command \documentstyle. There must be exactly one \documentclass command in a document; and it should normally come before any other command. (There are some exceptions, e.g., you can have filecontents environments before it or \RequirePackage but these should be only used in special scenarios as discussed elsewhere.)

option-list

The ⟨option-list⟩ is a list of options, each of which may modify the formatting of elements which are defined in the ⟨class-name⟩ file, as well as those in all following \usepackage commands (see below).

release-date

The optional argument ⟨release-date⟩ can be used to specify the earliest desired release date of the class file; it should contain a date in the format yyyy/mm/dd. If a version of the class older than this date is found, a warning is issued.

Example

\documentclass[twocolumn]{article}[1994/06/01]

\documentstyle

\documentstyle [⟨option-list⟩] {⟨class-name⟩}

This command is still supported for compatibility with old files. It is essentially the same as \documentclass except that it invokes LaTeX 2.09 compatibility mode. It also causes any options in the ⟨option-list⟩ that are not processed by the class file to be loaded as packages after the class has been loaded. See Section 4 for more details on LaTeX 2.09 compatibility mode.

\usepackage

\usepackage [⟨option-list⟩] {⟨package-name⟩} [⟨release-date⟩]

Any number of \usepackage commands is allowed. Each package file (as denoted by ⟨package-name⟩) defines new elements (or modifies those defined in the class file loaded by the ⟨class-name⟩ argument of the \documentclass command). A package file thus extends the range of documents which can be processed.

option-list

The ⟨option-list⟩ argument can contain a list of options, each of which can modify the formatting of elements which are defined in this ⟨package-name⟩ file.

release-date

As above, ⟨release-date⟩ can contain the earliest desired release date of the package file in the format yyyy/mm/dd; if an older version of the package is found, a warning is issued.

\usepackage[dvips]{graphics}[1994/06/01]

Each package is loaded only once. If the same package is requested more than once, nothing happens in the second or following attempt unless the package has been requested with options that were not given in the original \usepackage. If such extra options are specified then an error message is produced. See Section 6 how to resolve this problem. As well as processing the options given in the ⟨option-list⟩ of the \usepackage command, each package processes the ⟨option-list⟩ of the \documentclass command as well. This means that any option which should be processed by every package (to be precise, by every package that specifies an action for it) can be specified just once, in the \documentclass command, rather than being repeated for each package that needs it.

\listfiles

If this command is placed in the preamble then a list of the files read in (as a result of processing the document) will be displayed on the terminal (and in the log file) at the end of the run. Where possible, a short description will also be produced. Warning: this command will list only files which were read using LaTeX commands such as \input{⟨file⟩} or \include{⟨file⟩}. If the file was read using the primitive TeX syntax \input file (without { } braces around the file name) then it will not be listed; failure to use the LaTeX form with the braces can cause more severe problems, possibly leading to overwriting important files, so always put in the braces.

\setcounter

\setcounter{errorcontextlines} {⟨num⟩}

TeX3 introduced a new primitive \errorcontextlines which controls the format of error messages. LaTeX 2e provides an interface to this through the standard \setcounter command. As most LaTeX users do not want to see the internal definitions of LaTeX commands each time they make an error, LaTeX 2e sets this to −1 by default.

Environments {filecontents}

Until the LaTeX release in 2019 the filecontents environment was restricted to a place before the \documentclass command. These days it can be used anywhere, though we still think that in most cases it is best to only use it a the top of your document or in the preamble.

\begin{filecontents} [⟨option-list⟩] {⟨file-name⟩}
⟨file-contents⟩
\end{filecontents}

The filecontents environment is intended for bundling within a single document file the contents of packages, options, or other files. When the document file is run through LaTeX2e the body of this environment is written verbatim (preceded by a comment line) to a file whose name is given as the environment’s only argument. However, if that file already exists then nothing happens except for an information message. These days most UTF-8 text characters can be used in a filecontents environment - they will be written unchanged to the output file. However, tabs and form feeds produce a warning, explaining that they are turned into spaces or blank lines, respectively. By default the environment does not overwrite an existing file and it even refuses to write out the data if there exists a file that is anywhere in the path that TeX searches when inputting files. With the option nosearch you can ask it to look only into the current directory and with the option overwrite (or force) you can request it to write the file regardless. It will, however, never write to \jobname.tex to avoid overwriting itself. The filecontents environment is used for including LaTeX files. For other plain text files (such as Encapsulated PostScript files), you should use the filecontents* environment which does not add a comment line.

Document Structure

The book document class introduces new commands to indicate document structure.

\frontmatter
\mainmatter
\backmatter

These commands indicate the beginning of the front matter (title page, table of contents and prefaces), main matter (main text) and back matter (bibliography, indexes and colophon).

Definitions

In LaTeX, commands can have both mandatory and optional arguments, for example in:

\documentclass[11pt]{article}

the 11pt argument is optional, whereas the article class name is mandatory. In LaTeX 2.09 users could define commands with arguments, but these had to be mandatory arguments. With LaTeX2e, users can now define commands and environments which also have one optional argument.

\newcommand {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}
\newcommand* {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}
\renewcommand {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}
\renewcommand* {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}

These commands have a new, second, optional argument; this is used for defining commands which themselves take one optional argument. This new argument is best introduced by means of a simple (and hence not very practical) example:

\newcommand{\example}[2][YYY]{Mandatory arg: #2;
                              Optional arg: #1.}

This defines \example to be a command with two arguments, referred to as #1 and #2 in the {⟨definition⟩}—nothing new so far. But by adding a second optional argument to this \newcommand (the [YYY]) the first argument (#1) of the newly defined command \example is made optional with its default value being YYY. Thus the usage of \example is either:

\example{BBB}

which prints:

Mandatory arg: BBB; Optional arg: YYY.

or:

\example[XXX]{AAA}

which prints:

Mandatory arg: AAA; Optional arg: XXX.

The default value of the optional argument is YYY. This value is specified as the [ ⟨default⟩] argument of the \newcommand that created \example. As another more useful example, the definition:

\newcommand{\seq}[2][n]{\lbrace #2_{0},\ldots,\,#2_{#1} \rbrace}

means that the input $\seq{a}$ produces the formula {a₀,...,a_n}, whereas the input $\seq[k]{x}$ produces the formula {x₀,...,x_k}. In summary, the command:

\newcommand {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}

defines ⟨cmd⟩ to be a command with ⟨num⟩ arguments, the first of which is optional and has default value ⟨default⟩. Note that there can only be one optional argument but, as before, there can be up to nine arguments in total.

\newenvironment {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨beg-def⟩} {⟨end-def⟩}
\newenvironment* {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨beg-def⟩} {⟨end-def⟩}
\renewenvironment {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨beg-def⟩} {⟨end-def⟩}
\renewenvironment* {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨beg-def⟩} {⟨end-def⟩}

LaTeX2e also supports the creation of environments that have one optional argument. Thus the syntax of these two commands has been extended in the same way as that of \newcommand.

\providecommand {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}
\providecommand* {⟨cmd⟩} [⟨num⟩] [⟨default⟩] {⟨definition⟩}

This takes the same arguments as \newcommand. If ⟨cmd⟩ is already defined then the existing definition is kept; but if it is currently undefined then the effect of \providecommand is to define ⟨cmd⟩ just as if \newcommand had been used. All the above five ‘defining commands’ now have *-forms that are usually the better form to use when defining commands with arguments, unless any of these arguments is intended to contain whole paragraphs of text. Moreover, if you ever do find yourself needing to use the non-star form then you should ask whether that argument would not better be treated as the contents of a suitably defined environment. The commands produced by the above five ‘defining commands’ are now robust.

Boxes

These next three commands for making LR-boxes all existed in LaTeX 2.09. They have been enhanced in two ways.

\makebox [⟨width⟩] [⟨pos⟩] {⟨text⟩}
\framebox [⟨width⟩] [⟨pos⟩] {⟨text⟩}
\savebox {⟨cmd⟩} [⟨width⟩] [⟨pos⟩] {⟨text⟩}

One small but far-reaching change for LaTeX2e is that, within the ⟨width⟩ argument only, four special lengths can be used. These are all dimensions of the box that would be produced by using simply \mbox{⟨text⟩}: \heightits height above the baseline; \depthits depth below the baseline; \totalheightthe sum of \height and \depth; \widthits width. Thus, to put ‘hello’ in the centre of a box of twice its natural width, you would use:

\makebox[2\width]{hello}

Or you could put f into a square box.

\framebox{\makebox[\totalheight]{\itshape f\/}}

Note that it is the total width of the framed box, including the frame, which is set to \totalheight. The other change is a new possibility for ⟨pos⟩: s has been added to l and r. If ⟨ pos⟩ is s then the text is stretched the full length of the box, making use of any ‘rubber lengths’ (including any inter-word spaces) in the contents of the box. If no such ‘rubber length’ is present, an ‘underfull box’ will probably be produced.

\parbox [⟨pos⟩] [⟨height⟩] [⟨inner-pos⟩] {⟨width⟩} {⟨text⟩}
\begin{minipage} [⟨pos⟩] [⟨height⟩] [⟨inner-pos⟩] {⟨width⟩}
⟨text⟩
\end{minipage}

As for the box commands above, \height, \width, etc. may be used in the [⟨height⟩] argument to denote the natural dimensions of the box. The ⟨inner-pos⟩ argument is new in LaTeX2e. It is the vertical equivalent to the ⟨pos⟩ argument for \makebox, etc, determining the position of ⟨text⟩ within the box. The ⟨ inner-pos⟩ may be any one of t, b, c, or s, denoting top, bottom, centered, or ‘stretched’ alignment respectively. When the ⟨inner-pos⟩ argument is not specified, LaTeX gives it same value as ⟨pos⟩ (this could be the latter’s default value).

\begin{lrbox} {⟨cmd⟩}
⟨text⟩
\end{lrbox}

This is an environment which does not directly print anything. Its effect is to save the typeset ⟨text⟩ in the bin ⟨cmd⟩. Thus it is like \sbox {⟨cmd⟩} {⟨text⟩}, except that any white space before or after the contents ⟨text⟩ is ignored. This is very useful as it enables both the \verb command and the verbatim environment to be used within ⟨text⟩ . It also makes it possible to define, for example, a ‘framed box’ environment. This is done by first using this environment to save some text in a bin ⟨cmd⟩ and then calling \fbox{\usebox{⟨cmd⟩}}. The following example defines an environment, called fmpage, that is a framed version of minipage.

\newsavebox{\fmbox}
\newenvironment{fmpage}[1]
{\begin{lrbox}{\fmbox}\begin{minipage}{#1}}
{\end{minipage}\end{lrbox}\fbox{\usebox{\fmbox}}}

Measuring things

The first of these next commands was in LaTeX 2.09. The two new commands are the obvious analogues.

\settowidth {⟨length-cmd⟩} {⟨lr text⟩}
\settoheight {⟨length-cmd⟩} {⟨lr text⟩}
\settodepth {⟨length-cmd⟩} {⟨lr text⟩}

Line endings

The command \\, which is used to indicate a line-end in various places, is now a robust command when used within arguments such as section titles. Also, because it is often necessary to distinguish which type of line is to be ended, we have introduced the following new command; it has the same argument syntax as that of \\.

\tabularnewline [⟨vertical-space⟩]

One example of its use is when the text in the last column of a tabular environment is set with \raggedright; then \tabularnewline can be used to indicate the end of a row of the tabular, whilst \\ will indicate the end of a line of text in a paragraph within the column. This command can be used in the array environment as well as tabular, and also the extended versions of these environments offered by the array and longtable packages in the tools collection.

Controlling Page Breaks

Sometimes it is necessary, for a final version of a document, to ‘help’ LaTeX break the pages in the best way. LaTeX 2.09 had a variety of commands for this situation: \clearpage, \pagebreak etc. LaTeX2e provides, in addition, commands which can produce longer pages as well as shorter ones.

\enlargethispage {⟨size⟩}
\enlargethispage* {⟨size⟩}

These commands increase the height of a page (from its normal value of \textheight) by the specified amount ⟨size⟩, a rigid length. This change affects only the current page. This can be used, for example, to allow an extra line to be fitted onto the page or, with a negative length, to produce a page shorter than normal. The star form also shrinks any vertical white space on the page as much as possible, so as to fit the maximum amount of text on the page. These commands do not change the position of the footer text; thus, if a page is lengthened too far, the main text may overprint the footer.

Floats

There is a new command, \suppressfloats, and a new ‘float specifier’. These will enable people to gain better control of LaTeX’s float placement algorithm.

\suppressfloats [⟨placement⟩]

This command stops any further floating environments from being placed on the current page. With an optional argument, which should be either t or b (not both), this restriction applies only to putting further floats at the top or at the bottom. Any floats which would normally be placed on this page are placed on the next page instead. The extra float location specifier: ! This can be used, along with at least one of h, t, b and p, in the location optional argument of a float. If a ! is present then, just for this particular float, whenever it is processed by the float mechanism the following are ignored:

• all restrictions on the number of floats which can appear;
• all explicit restrictions on the amount of space on a text page which may be occupied by floats or must be occupied by text.

The mechanism will, however, still attempt to ensure that pages are not overfull and that floats of the same type are printed in the correct order. Note that its presence has no effect on the production of float pages. A ! specifier overrides the effect of any \suppressfloats command for this particular float.

Font changing: text

The font selection scheme used in LaTeX2e differs a lot from that used in LaTeX 2.09. In this section, we give a brief description of the new commands. A more detailed description with examples is given in The LaTeX Companion, and the interface for class- and package-writers is described in LaTeX2e Font Selection.

\normalfont
\rmfamily
\sffamily
\ttfamily
\mdseries
\bfseries
\upshape
\itshape
\slshape
\scshape

These are font commands whose use is the same as the commands \rm, \bf, etc. The difference is that each command changes just one attribute of the font (the attribute changed is part of the name). One result of this is that, for example, \bfseries\itshape produces both a change of series and a change of shape, to give a bold italic font.

\textnormal{⟨text⟩}
\textrm{⟨text⟩}
\textsf{⟨text⟩}
\texttt{⟨text⟩}
\textmd{⟨text⟩}
\textbf{⟨text⟩}
\textup{⟨text⟩}
\textit{⟨text⟩}
\textsl{⟨text⟩}
\textsc{⟨text⟩}
\emph{⟨text⟩}

These are one-argument commands; they take as an argument the text which is to be typeset in the particular font. They also automatically insert italic corrections where appropriate; if you do not like the result, you can add an italic correction with \/ or remove it with \nocorr. The \nocorr should always be the first or last thing within the {⟨text⟩} argument.

Font Changing: math

Most of the fonts used within math mode do not need to be explicitly invoked; but to use letters from a range of fonts, the following class of commands is provided.

\mathrm {⟨letters⟩}
\mathnormal {⟨letters⟩}
\mathcal {⟨letters⟩}
\mathbf {⟨letters⟩}
\mathsf {⟨letters⟩}
\mathtt {⟨letters⟩}
\mathit {⟨letters⟩}

These are also one-argument commands which take as an argument the letters which are to be typeset in the particular font. The argument is processed in math mode so spaces within it will be ignored. Only letters, digits and accents have their font changed, for example $\mathbf{\tilde A \times 1}$ produces ̃A×1.

Ensuring math mode

\ensuremath {⟨math commands⟩}

In LaTeX 2.09, if you wanted a command to work both in math mode and in text mode, the suggested method was to define something like:

\newcommand{\Gp}{\mbox{$G_p$}}

Unfortunately, the \mbox stops \Gp changing size correctly in (for instance) subscripts or a fraction. In LaTeX2e you can define it thus:

\newcommand{\Gp}{\ensuremath{G_p}}

This is because the \ensuremath does nothing, producing simply G_p, when \Gp is used within math mode; but it ensures that math mode is entered (and exited) as required when \Gp is used in text mode.

Setting text superscripts

\textsuperscript {⟨text⟩}

In LaTeX 2.09 textual superscripts such as footnote markers were produced by internally entering math mode and typesetting the number as a math super- script. This normally looked fine since the digits in math fonts are the same as those in text fonts when Computer Modern fonts are used. But when a different document font (such as Times) is selected, the results look rather strange. For this reason the command \textsuperscript has been introduced which typesets its argument in the current text font, in a superscript position and in the correct size.

Text commands: all encodings

One of the main differences between LaTeX2ε and LaTeX2.09 is that LaTeX2ε can deal with fonts in arbitrary encodings. (A font encoding is the sequence of characters in the font—for example a Cyrillic font would have a different encoding from a Greek font.) The two major font encodings that are used for Latin languages such as English or German are OT1 (Donald Knuth’s 7-bit encoding, which has been used during most of TeX’s lifetime) and T1 (the new 8-bit ‘Cork’ encoding). LaTeX2.09 only supported the OT1 encoding, whereas LaTeX2e has support for both OT1 and T1 built-in. The next section will cover the new commands which are available if you have T1-encoded fonts. This section describes new commands which are available in all encodings. Most of these commands provide characters which were available in LaTeX2.09 already. For example \textemdash gives an ‘em dash’, which was available in LaTeX2.09 by typing ---. However, some fonts (for example a Greek font) may not have the --- ligature, but you will still be able to access an em dash by typing \textemdash.

\r{⟨text⟩}

This command gives a ‘ring’ accent, for example ‘ ̊o’ can be typed \r{o}.

\SS

This command produces a German ‘SS’, that is a capital ‘ß’. This letter can hyphenate differently from ‘SS’, so is needed for entering all-caps German.

\textcircled{⟨text⟩}

This command is used to build ‘circled characters’ such as \copyright. For example \textcircled{a} produces a○.

\textcompwordmark

This command is used to separate letters which would normally ligature. For example ‘fi’ is produced with f\textcompwordmark i. Note that the ‘f’ and ‘i’ have not ligatured to produce ‘fi’. This is rarely useful in English (‘shelfful’ is a rare example of where it might be used) but is used in languages such as German.

\textvisiblespace

This command produces a ‘visible space’ character ‘ ’. This is sometimes used in computer listings, for example ‘type hello world’.

\textemdash \textendash \textexclamdown \textquestiondown
\textquotedblleft \textquotedblright \textquoteleft \textquoteright

These commands produce characters which would otherwise be accessed via ligatures: ligaturecharactercommand ------\textemdash ----\textendash !'!\textexclamdown ?'?\textquestiondown ''''\textquotedblleft ````\textquotedblight ''\textquoteleft ``\textquoteright The reason for making these characters directly accessible is so that they will work in encodings which do not have these characters.

\textbullet \textperiodcentered

These commands allow access to characters which were previously only available in math mode: math commandcharactertext command \bullet.\textbullet \cdot.\textperiodcentered

\textbackslash \textbar \textless \textgreater

These commands allow access to ASCII characters which were only available in verbatim or math mode: math commandcharactertext command \backslash\\textbackslash \mid|\textbar <<\textless >>\textgreater

\textasciicircum \textasciitilde

These commands allow access to ASCII characters which were previously only available in verbatim: verbatimtext command ^\textasciicircum ~\textasciitilde

\textregistered \texttrademark

These commands provide the ‘registered trademark’ (R) and ‘trademark’ (TM) symbols.

Text commands: the T1 encoding

The OT1 font encoding is fine for typesetting in English, but has problems when typesetting other languages. The T1 encoding solves some of these problems, by providing extra characters (such as ‘eth’ and ‘thorn’), and it allows words containing accented letters to be hyphenated (as long as you have a package like babel which allows for non-American hyphenation). This section describes the commands you can use if you have the T1 fonts. To use them, you need to get the ‘ec fonts’, or the T1-encoded PostScript fonts, as used by psnfss. All these fonts are available by anonymous ftp in the Comprehensive TeX Archive, and are also available on the CD-ROMs 4all TeX and TeX Live (both available from the TeX Users Group). You can then select the T1 fonts by saying:

\usepackage[T1]{fontenc}

This will allow you to use the commands in this section. Note: Since this document must be processable on any site running an up-to-date LaTeX, it does not contain any characters that are present only in T1-encoded fonts. This means that this document cannot show you what these glyphs look like! If you want to see them then run LaTeX on the document fontsmpl and respond ‘cmr’ when it prompts you for a family name.

\k{⟨text⟩}

This command produces an ‘ogonek’ accent.

\DH \DJ \NG \TH \dh \dj \ng \th

These commands produce characters ‘eth’, ‘dbar’, ‘eng’, and ‘thorn’.

\guillemotleft \guillemotright \guilsinglleft \guilsinglright
\quotedblbase \quotesinglbase \textquotedbl

These commands produce various sorts of quotation mark. Rough representa- tions of them are: ≪a≫ ,,a“ ,a‘ and "a". There are therefore some extra short-form ligatures available for use in documents that will only be used with T1-encoded fonts. The guillemets \guillemotleft and \guillemotright can be obtained by typing << and >> and \quotedblbase by typing ,,. Also, unlike the unexpected results with OT1-encoded fonts, < and > will produce < and >. Note also that the single character " will no longer produce ” but rather \textquotedbl.

Logo

\LaTeX
\LaTeXe

\LaTeX (producing ‘LATEX’) is still the ‘main’ logo command, but if you need to refer to the new features, you can write \LaTeXe (producing ‘LATEX 2ε’).

Picture Commands

\qbezier[⟨N⟩](⟨AX⟩,⟨AY⟩)(⟨BX⟩,⟨BY⟩)(⟨CX⟩,⟨CY⟩)
\bezier{⟨N⟩}(⟨AX⟩,⟨AY⟩)(⟨BX⟩,⟨BY⟩)(⟨CX⟩,⟨CY⟩)

The \qbezier command can be used in picture mode to draw a quadratic Bezier curve from position (⟨AX⟩,⟨AY⟩) to (⟨CX⟩,⟨CY⟩) with control point (⟨BX⟩,⟨BY⟩). The optional argument ⟨N⟩ gives the number of points on the curve. For example, the diagram: is drawn with:

\begin{picture}(50,50)
\thicklines
\qbezier(0,0)(0,50)(50,50)
\qbezier[20](0,0)(50,0)(50,50)
\thinlines
\put(0,0){\line(1,1){50}}
\end{picture}

The \bezier command is the same, except that the argument ⟨N⟩ is not optional. It is provided for compatibility with the LATEX 2.09 bezier document style option.

Old Commands

\samepage

The \samepage command still exists but is no longer being maintained. This is because it only ever worked erratically; it does not guarantee that there will be no page-breaks within its scope; and it can cause footnotes and marginals to be wrongly placed. We recommend using \enlargethispage in conjunction with page-break commands such as \newpage and \pagebreak to help control page breaks.

\SLiTeX

Since SliTEX no longer exists, the logo is no longer defined in the LATEX kernel. A suitable replacement is \textsc{Sli\TeX}. The SliTEX logo is defined in LATEX 2.09 compatibility mode.

\mho \Join \Box \Diamond \leadsto
\sqsubset \sqsupset \lhd \unlhd \rhd \unrhd

These symbols are contained in the LATEX symbol font, which was automatically loaded by LATEX 2.09. However, TEX has room for only sixteen math font families; thus many users discovered that they ran out. Because of this, LATEX does not load the LATEX symbol font unless you use the latexsym package. These symbols are also made available, using different fonts, by the amsfonts package, which also defines a large number of other symbols. It is supplied by the American Mathematical Society. The latexsym package is loaded automatically in LATEX 2.09 compatibility mode.

LaTeX 2.09 Documents

LATEX 2ε can process (almost) any LATEX 2.09 document, by entering LATEX 2.09 compatibility mode. Nothing has changed, you run LATEX in the same way you always did, and you will get much the same results. The reason for the ‘almost’ is that some LATEX 2.09 packages made use of low- level unsupported features of LATEX. If you discover such a package, you should find out if it has been updated to work with LATEX 2ε. Most packages will still work with LATEX 2ε—the easiest way to find out whether a package still works is to try it! LATEX 2.09 compatibility mode is a comprehensive emulation of LATEX 2.09, but at the cost of time. Documents can run up to 50% slower in compatibility mode than they did under LATEX 2.09. In addition, many of the new features of LATEX 2 ε are not available in LATEX 2.09 compatibility mode.

Warning

This LATEX 2.09 compatibility mode is provided solely to allow you to process 2.09 documents, i.e. documents that were written (we hope, a long time ago) for a very old system and therefore could be processed by using a genuine antique LATEX 2.09 system. This mode is therefore not intended to provide access to the enhanced features of LATEX 2ε. Thus it must not be used to process new documents which masquerade as 2.09 documents (i.e. they begin with \documentstyle) but which could not be processed using that genuine antique LATEX 2.09 system because they contain some new, LATEX 2ε-only, commands or environments. To prevent such misuse of the system, and the consequent trouble it causes when such misleadingly encoded documents are distributed, the LATEX 2.09 compatibility mode turns off most of these new features and commands. Any attempt to use them will give you an error message and, moreover, many of them simply will not work, whilst others will produce unpredictable results. So don’t bother sending us any bug reports about such occurrences since they are intentional.

Font selection problems

When using compatibility mode, it is possible that you will find problems with font-changing commands in some old documents. These problems are of two types:

• producing error messages;
• not producing the font changes you expected.

In case of error messages it is possible that the document (or an old style file used therein) contains references to old internal commands which are no longer defined, see Section 6.2 for more information if this is the case. One example of the unexpected is if you use one of the new style of math-mode font changing command as follows:

$ \mathbf{xy} A $

You may well find that this behaves as if you had put:

$ \bf {xy} A $

everything including the A coming out bold. LATEX 2.09 allowed sites to customize their LATEX installation, which resulted in documents producing different results on different LATEX installations. LATEX 2ε no longer allows so much customization but, for compatibility with old documents, the local configuration file latex209.cfg is loaded every time LATEX 2ε enters LATEX 2.09 compatibility mode. For example, if your site was customized to use the New Font Selection Scheme (NFSS) with the oldlfont option, then you can make LATEX 2ε emulate this by creating a latex209.cfg file containing the commands:

\ExecuteOptions{oldlfont}\RequirePackage{oldlfont}

Similarly, to emulate NFSS with the newlfont option, you can create a latex209.cfg file containing:

\ExecuteOptions{newlfont}\RequirePackage{newlfont}

Native mode

To run an old document faster, and use the new features of LaTeX2ε, you should try using LaTeX2ε native mode. This is done by replacing the command:

\documentstyle[⟨options⟩,⟨packages⟩]{⟨class⟩}

with:

\documentclass[⟨options⟩]{⟨class⟩}
\usepackage{latexsym,⟨packages⟩}

However, some documents which can be processed in LaTeX2.09 compatibility mode may not work in native mode. Some LaTeX2.09 packages will only work with LaTeX2ε in 2.09 compatibility mode. Some documents will cause errors because of LaTeX2ε’s improved error detection abilities. But most LaTeX2.09 documents can be processed by LaTeX2ε’s native mode with the above change. Again, the easiest way to find out whether your documents can be processed in native mode is to try it!

Local modifications

There are two common types of local modifications that can be done very simply. Do not forget that documents produced using such modifications will not be usable at other places (such documents are called ‘non-portable’). One type of modification is the use of personal commands for commonly used symbols or constructions. These should be put into a package file (for example, one called mymacros.sty) and loaded by putting \usepackage{mymacros} in the document preamble. Another type is a local document class that is very similar to one of the standard classes but contains some straightforward modifications such as extra environ- ments, different values for some parameters, etc. These should be put into a class file; here we shall describe a simple method of constructing such a file using, as an example, a class called larticle that is very similar to the article class. The class file called larticle.cls should (after the preliminary identification commands) start as follows:

\LoadClassWithOptions{article}

This command should be followed by whatever additions and changes you wish to make to the results of reading in the file article.sty. The effect of using the above \LoadClassWithOptions command is to load the standard class file article with whatever options are asked for by the document. Thus a document using your larticle class can specify any option that could be specified when using the standard article class; for example:

\documentclass[a4paper,twocolumn,dvips]{larticle}

Problems

This section describes some of the things which may go wrong when using LaTeX2ε, and what you can do about it.

New error messages

LaTeX2ε has a number of new error messages. Please also note that many error messages now produce further helpful information if you press h in response to the error prompt.

Option clash for package ⟨package⟩.

The named package has been loaded twice with different options. If you enter h you will be told what the options were, for example, if your document contained:

\usepackage[foo]{fred}
\usepackage[baz]{fred}

then you will get the error message:

Option clash for package fred.

and typing h at the ? prompt will give you:

The package fred has already been loaded with options:
[foo]
There has now been an attempt to load it with options:
[baz]
Adding the line:
\usepackage[foo,baz]{fred}
to your document may fix this.
Try typing <return> to proceed.

The cure is, as suggested, to load the package with both sets of options. Note that since LaTeXpackages can call other packages, it is possible to get a package option clash without explicitly requesting the same package twice.

Command ⟨command⟩ not provided in base NFSS.

The ⟨command⟩ is not provided by default in LaTeX2ε. This error is generated by using one of the commands:

\mho \Join \Box \Diamond \leadsto
\sqsubset \sqsupset \lhd \unlhd \rhd \unrhd

which are now part of the latexsym package. The cure is to add:

\usepackage{latexsym}

in the preamble of your document.

LaTeX2e command ⟨command⟩ in LaTeX 2.09 document.

The ⟨command⟩ is a LaTeX2ε command but this is a LaTeX2.09 document. The cure is to replace the command by a LaTeX2.09 command, or to run document in native mode, as described in Section 4.3.

NFSS release 1 command \newmathalphabet found.

The command \newmathalphabet was used by the New Font Selection Scheme Release 1 but it has now been replaced by \DeclareMathAlphabet, the use of which is described in LaTeX2ε Font Selection. The best cure is to update the package which contained the \newmathalphabet command. Find out if there is a new release of the package, or (if you wrote the package yourself) consult LaTeX2ε Font Selection for the new syntax of font commands. If there is no updated version of the package then you can cure this error by using the newlfont or oldlfont package, which tells LaTeXwhich version of \newmathalphabet should be emulated. You should use oldlfont if the document selects math fonts with syntax such as this:

{\cal A}, etc.

Use newlfont if the document’s syntax is like this:

\cal{A}, etc.

Text for \verb command ended by end of line.

The \verb command has been begun but not ended on that line. This usu- ally means that you have forgotten to put in the end-character of the \verb command.

Illegal use of \verb command.

The \verb command has been used inside the argument of another command. This has never been allowed in LaTeX—often producing incorrect output without any warning—and so LaTeX2ε produces an error message.

Old internal commands

A number of LaTeX2.09 internal commands have been removed, since their functionality is now provided in a different way. See LaTeX2ε for Class and Package Writers for more details of the new, supported interface for class and package writers.

\tenrm \elvrm \twlrm. . .
\tenbf \elvbf \twlbf. . .
\tensf \elvsf \twlsf. . .
.
.
.

These commands provided access to the seventy fonts preloaded by LaTeX2.09. In contrast, LaTeX2ε normally preloads at most fourteen fonts, which saves a lot of font memory; but a consequence is that any LaTeXfile which used the above commands to directly access fonts will no longer work. Their use will usually produce an error message such as:

! Undefined control sequence.
l.5 \tenrm

The cure for this is to update the document to use the new font-changing commands provided by LaTeX2ε; these are described in LaTeX2ε Font Selection. If this is not possible then, as a last resort, you can use the rawfonts package, which loads the seventy LaTeX2.09 fonts and provides direct access to them using the old commands. This takes both time and memory. If you do not wish to load all seventy fonts, you can select some of them by using the only option to rawfonts. For example, to load only tenrm and tenbf you write:

\usepackage[only,tenrm,tenbf]{rawfonts}

The rawfonts package is distributed as part of the LaTeXtools software, see Section 2.4.

Old files

One of the more common mistakes in running LaTeXis to read in old versions of packages instead of the new versions. If you get an incomprehensible error message from a standard package, make sure you are loading the most recent version of the package. You can find out which version of the package has been loaded by looking in the log file for a line like:

Package: fred 1994/06/01 v0.01 Fred’s package.

You can use the ⟨release-date⟩ options to \documentclass and \usepackage to make sure that you are getting a suitably recent copy of the document class or package. This is useful when sending a document to another site, which may have out-of-date software.

Where to go for more help

If you can’t find the answer for your problem here, try looking in LaTeX: A Document Preparation System or The LaTeX Companion. If you have a problem with installing LaTeX, look in the installation guide files which come with the distribution. If this doesn’t help, contact your local LaTeXguru or local LaTeXmailing list. If you think you’ve discovered a bug then please report it! First, you should find out if the problem is with a third-party package or class. If the problem is caused by a package or class other than those listed in Section 2 then please report the problem to the author of the package or class, not to the LaTeX3 project team. If the bug really is with core LaTeX then you should create a short, self-contained document which exhibits the problem. You should run a recent (less than a year old) version of LaTeXon the file and then run LaTeX on latexbug.tex. This will create an error report which you should send, together with the sample document and log file, to the LaTeXbugs address which can be found in the file latexbug.tex or bugs.txt.

Example

Code

%%Initial Commands Division begin
\begin{filecontents}{file-name}
File 'file-name.tex' is saved
\end{filecontents}
%%Initial Commands Division end
%%Document Class Division begin
\documentclass{article} 
%%Document Class Division end
%%Preamble Commands Division begin
\usepackage[papersize={100mm,50mm} , total={40mm,10mm},showframe]{geometry}
%%Preamble Commands Division end
%%Document Environment Division begin
\begin{document}
Document...
\end{document}
%%Document Environment Division end
%%End Division begin
Ending
%%End Division end

Output 'file-name.tex' File

%% LaTeX2e file `file-name'
%% generated by the `filecontents' environment
%% from source `latex_document_structure_001a' on 2022/02/22.
%%
File 'file-name.tex' is saved

Output

 

Source and Reference

• https://www.latex-project.org/help/documentation/usrguide.pdf
• Michel Goossens, Sebastian Rahtz and Frank Mittelbach. The LATEX Graphics Companion. Addison-Wesley, Reading, Massachusetts, 1997.
• Michel Goossens and Sebastian Rahtz. The LaTeX Web Companion. Addison-Wesley, Reading, Massachusetts, 1999.
• Donald E. Knuth. The TEXbook. Addison-Wesley, Reading, Massachusetts, 1986. Revised to cover TEX3, 1991.
• Leslie Lamport. LaTeX : A Document Preparation System. Addison-Wesley, Reading, Massachusetts, second edition, 1994.
• Frank Mittelbach and Michel Goossens. The LaTeX Companion second edi- tion. With Johannes Braams, David Carlisle, and Chris Rowley. Addison-Wesley, Reading, Massachusetts, 2004.